1. Field of the Invention
The invention relates to space vehicles. In particular, the invention relates to provision of artificial gravity in space vehicles.
2. Description of the Related Art
Since Isaac Newton enunciated his laws of motion and gravitation, humanity has been aware that all humans are bound to Earth by a force called gravity. Upon achieving powered flight in the twentieth century, it became evident that the magnitude of the force of gravity upon a human being in an aircraft flight can reach many times the force of gravity on Earth's surface or ground level, and in some conditions, even lower than the force of gravity at ground level. Also in the twentieth century, man has achieved flight in Earth orbit and in space beyond Earth. In these environments, and depending upon space flight conditions, man is exposed to gravity forces which can vary, from many times Earth's surface gravity to infinitesimally low fractions thereof, referred to herein as "microgravity" or simply "zero gravity". Microgravity normally prevails in a space vehicle during cruising flight, that is, when flight thrust or attitude control forces are not being applied to the space vehicle.
Man has developed in a ground level environment since his remote origins, so it is not surprising that his body systems are unable to function undisturbed when in microgravity environments encountered in space travel. Affected are the skeletal, muscular, cardiovascular, nervous and sundry other body systems, as also their physiological processes. The severity of the various afflictions is a function of the length of time of exposure. It is known in the art that after only half-dozen days in Earth orbit, astronauts lose about one percent of their biomass. Physical weakness is normally experienced by astronauts after their return to Earth. Thereafter recovery is achieved after suitable treatment, evidence of the deleterious nature of microgravity on the human body and the necessity for developing effective countermeasures if man is to succeed in long duration space travel over periods encompassing months or even years.
Exemplary of Patents of the related Prior Art are the following U.S. Pat. Nos. 3,073,040; 3,675,879; 3,749,332; 4,643,375; 5,580,130; and 5,302,013.
Recognition of the deleterious effect on human body systems due to a microgravity environment in space flight came early. The problem continues to be what to do about it. Essentially, countermeasures have been considered for space vehicle design and through body exercise performed by astronauts in space flight. The various routines of body exercise performed by astronauts during space flight have not arrested the problems of microgravity, and only marginally reduced its severity. Expectations remain that drugs some day will be discovered which avoid any damage to astronauts from microgravity.
Some suggested vehicle design features to counter microgravity by producing artificial gravity provide for the rotation of the entire space vehicle in various ways. However, when the entire space vehicle is spinning, provision of forward thrust for vehicle propulsion becomes complex in design and execution.
For a trip to Mars, which may last in excess of ten months in transit one way, it has been suggested to revolve a vehicle containing astronauts and a rocket engine module, each a either end of a long and rigid beam or "tether".
Another suggestion has been to use a vehicle geometry equivalent to a doughnut or tire inner tube. All of the crew of astronauts would be confined within this toroidal enclosure spinning at the required rate to achieve the desired artificial gravity. Non-living components would be located within the space toward the axis of rotation of the toroidal space vehicle. Propulsion engines would be aligned parallel to or coincident with the axis of rotation, at the point of a vehicle which would resemble a large spinning top. An alternate arrangement for the propulsion engines for the spinning toroid would be to use at the rotational axis a main axle for the toroidal "wheel". At either end of this axle, and perpendicular to it, would be the propulsion engines to provide a balanced thrust. The whole vehicle thus would resemble a single rotating wheel with "handles" attached at either end of its axle, in the manner of a wheelbarrow.
The fictional but popular "flying saucer" is a prototypical space vehicle, provided not only with propulsion capabilities but with the avoidance of microgravity problems or countermeasures.
Actual experience in microgravity countermeasures is very limited at the present time. Various routines of body exercise performed by astronauts during space flight only marginally reduces the severity of damage to the body caused by long-term exposure to microgravity environments.
There is no known experimental data on human subjects that can be used as a guide to determine the critical unknowns of the human threshold of microgravity tolerance, and therefore the magnitude, duration, and cycling frequency of artificial gravity to supply to prevent microgravity damage to astronauts. Experimental programs in space to test the variables of artificial gravity for arresting microgravity damage are essential to assure the success of long-term space missions such as manned trips to Mars.
It is thus recognized that damage to skeletal, muscular, cardiovascular and other systems of the body of an astronaut occurs when engaged in space flight, where microgravity is encountered.
It is an object of the present invention to provide a mechanism for producing artificial gravity for individuals in microgravity space environments at levels necessary to arrest any potential body damage.
It is an additional object of the present invention to provide artificial gravity to a module or modules in a space vehicle containing one or more astronauts, rather than providing artificial gravity to the space vehicle as a whole.